Pressurized gas supply networks are known in which it is required to provide a gas outlet station which cooperates with a detachable adaptor for selective transfer of gas flow under pressure from a gas supply conduit via such adaptors to secondary equipment for ultimate use of the gas.
For example, in medical treatment environments, it is commonplace to have available in a plurality of treatment areas wall or ceiling mounted gas outlet stations which are supplied by a permanently installed gas supply system with such medically useful gases as nitrogen, carbon dioxide, air, oxygen or nitrous oxide, each usually being supplied from a storage tank which may be quite remote from any area of ultimate use of the gas. Such outlet stations may also include a vacuum or suction line connection or other desirable gaseous fluid flow service connections.
For each different gas or service available at an outlet station the outlet station commonly includes an adaptor connection assembly which is opened when connected with the proper adaptor to deliver gas via the adaptor to the connected secondary equipment or user, and is closed leak tight when the adaptor is disconnected therefrom to preclude leakage of pressurized gas from the system into the ambient air.
Each adaptor connection assembly in the outlet station typically may be mounted together with a face plate assembly and a mounting box which is permanently installed in the wall or ceiling of the treatment area and to which the proper gas supply conduit is routed.
In the prior art of such gas supply systems it is known to provide schemes of non-redundant keying to ensure error free gas connections. For example, such keying schemes have been applied to ensure proper adaptor-to-outlet station connections. Two common approaches to such adaptor keying are the DISS or Diameter Indexed Safety System, and the Quick Connect System. In DISS, the gas outlet valves for each of a plurality of different gases or services include specified diametrical dimensioning for adaptor receiving portions thereof which differ from the corresponding dimensions of all other such outlet valves whereby only one of a corresponding plurality of adaptors will fit each such outlet valve. In the Quick Connect or QC System each adaptor includes an elongated valve plug which is engagable with the respective outlet valve when manually thrusted into engagement therewith. The engagement establishes a leak tight gas flow connection and the connection is secured or latched by a pin latch mechanism separate from the valve plug. The latching pin and the elongated valve plug commonly are disposed in spaced parallel relationship with the spacing therebetween defining a keyed relationship such that each quick connect adaptor is engagable only with an outlet station having a corresponding lateral spacing between the valve element and the latch pin engaging mechanism.
Just as proper adaptor-to-outlet station connections are of critical importance in medical gas supply systems, so too are proper matching of the various outlet station valves, face plates and latching assemblies to the permanently installed mounting box and the gas supply conduit associated therewith. The potential severity of the consequences of improper outlet station assembly is of such magnitude as to dictate a very high standard of care. Accordingly, non-redundant keying schemes are also known in the art for keying outlet valves to mounting boxes, face plate assemblies to valves or mounting boxes, and the like, in order to ensure error free assembly of the various outlet station components during system installation.
The prior art includes numerous examples of gas outlet station valve assemblies and cooperating adaptors, of which the following are exemplary: U.S. Pat. Nos. 2,908,511, 3,448,760, 3,544,257, 3,563,267, and 3,643,985.
Notwithstanding the efficacy of prior keyed assembly schemes, certain shortcomings of the prior art have been noted. For example, the commercial acceptance of two connection systems, QC and DISS, has precipitated the evolution of two distinct and mutually incompatible approaches to outlet station construction thus severely limiting the use of universal components in gas supply system design. Another shortcoming of some prior art designs has been the failure thereof to provide for non-redundant keying in all installation configurations. For example, in some wall mounted systems designers have relied on the obvious up and down orientation of the face plate or other components to establish proper orientation thereof (e.g., the component is properly oriented when a label or other indicia thereon is upright). This approach functions more in the nature of a guide than a keying scheme and as such does not necessarily offer the desired non-redundancy of a proper keying scheme. In ceiling outlet station installations of such systems the up and down orientation guide is lost thus introducing the possibility of improper assembly.
Still another shortcoming reflected in the prior art has been the need in DISS systems for a keying system which non-redundantly keys all components without requiring the DISS valve body to be carried on the face plate assembly. In this regard, it has been found advantageous to permit the DISS face plate assembly to be removed from the outlet station without removing the DISS valve whereby to allow ready access to the in-place valve for the purpose of performing leak check inspection during routine maintenance. However, Key Systems for DISS outlet stations have heretofore either provided no keying for the DISS valve, or have required the permanent attachment of the valve to the DISS face plate.
Additionally, prior art keying systems for both DISS and QC services have required an inventory of many gas-specific parts by manufacturers of the keyed outlet stations. This shortcoming has encouraged such manufacturers to limit the number of gas-specific selections for users of outlet stations because the production of low quantities of stations for unusual gas services has heretofore proved uneconomical.